Zemectin/ivermectin Worms Are Surviving?

Question

Okay, I got off the phone with one of my horse kids who just informed me that she had several horses rubbing their tails. She did back to back worming with Ivermectin and they were still rubbing!

So, she called her local Vet in Agua Dulce, CA, Dr. Connelly. He stated that the worms are building up an immunity to the old tried and true method of paste worming.

Dr. Connelly told her to hit them with Panacur Power Pac.

Anybody else ever heard anything about this?

Answer 1

I use a rotation schedule prescribed by my vet.  I think I used strongid in May, now this month is an ivermec product.  I think...I'd have to check to be sure.

I did have a horse with encysted strongyles and the double dose panacur did WONDERS for him.

But here's a money saver for her...just get enough LIQUID panacur from the vet to give a double dose for 5 days...for my gelding, it was 40 cc per day.  MUCH cheaper, and the results are the same.  I think panacur standard dose is 1cc/50 lbs?  That works out right...20 cc for a 1000 lb horse, doubled would be 40cc  (Sorry...doing the math)

I took a 60 cc syringe with the catheter tip, placed my finger over the end, filled it up to 40, placed the plunger over the end to seal, flipped it over and squeezed the air out, then popped it as far back in the mouth as possible.  Not difficult at all.

Oh and for the shithead thumbs downer...this was done upon advice of the equine specialist for whom I work on prn basis, not something I pulled out of my ***.  The reason the power pac or the double dose method works is it disrupts the cycle for several days, thus, several stages of the cycle.  It is repeated over a period of several days.  Panacur has no lethal dosage, so it is very very safe to give, even to puppies.

Duh

Answer 2

Yes, and just think about how many people are feeding daily wormers.... You need to tell her to go to a local tackshop and they will help her get on a 3 way rotational de-wormer schedule.. Trust me it works wonders.. :)

Answer 3

it is not uncommon for worms to work up an immunity.i dont know about panacur because i havent used it but i rotate between ivermectin,oxybendazole,moxydectin and pyrantel pamoate and havent had a severe case where i needed it.i do use fenbendazole which is the active ingredient in panacur for my cattle.sounds like good advice from the vet.

Answer 4

No I hadn't heard... But it makes a lot of sense. I don't worm bi-monthly like most. I only worm when I need to or when a new horse enters the property. It's good information to know regardless so I appreciate it! Something to keep in mind!

Answer 5

Ivermectin is only good for things like bots. You have to find something else for pin worms, not quick sure what off the top of my head. The Panacur Power Pac is really expensive if I remember correctly and I would just find the right wormer for your horse. You can also use Listerine (the human mouth wash) and rub it in their tales and then wash it out. Good luck!

Answer 6

I just got the email today. Roundworm has become resistent to both ivermectin and pyrantel.  Fenbutazole and oxibenzadole are still effective against roundworm.

Ivermectin is still effective against small strongyles, but the populations are returning at a more rapid rate and they don't know why yet.  The other paraciticides I mentioned above are not effective against small strongyles.

There is nothing in the working to kill these larvae/worms if they become completely resistent.

Answer 7

Ivermectin's never been anywhere near 100% against pinworms.  The problem is, the female lays the eggs outside the body, so when the ivermectin's delivered they don't get killed.  Multiple doses help, but do not cure.

You have to use a wormer with a residual effect, which ivermectin doesn't have.  That's why ivermectin doesn't build immunity in parasites - it doesn't hang around in subclinical doses to acclimate the little buggers.

Second hand info... the kid says the doc says...  I question it.   Something was probably misstated or misunderstood.

Answer 8

Yep.  Ivermectin advertised itself as a wormer that you didnt need to rotate.  And the result is.. imunity by the worms.

My vet talked about it over a year ago,  he also talked about how horses build some imunity to certain worms as foals but ivermectin interfered with that.

Answer 9

WEll, my vet didn't say anything about tolerance, she just told me when I had his teeth floated that I shouldtry to fit in a Panacur Power Pac into my rotation schedule.  I did see a horse rubbing her butt today, and me and the other girl thinks she might have worms, but IDK if that horses owner wormed her.

Answer 10

I have heard of an immunity being built to the same worming brand being used time after time. If they are rotating brands (ivermectin, moxidectin, pyrantel pamoate, etc), then worms shouldn't become immune. I have been given different worming schedules through different vets, friends, trainers, and horse people. I found one on the internet that I really like. http://www.horsehealthusa.com/cgi-local/...

Answer 11

No I have not. Thanks Rosi thats a great help. I normaly rotate my wormer. But now I got one more thing to add to the rotation. Its not suprising, realy. How long have we all used Ivermec and Zemectin on our horses for how many years. Kinda like how if you use a lot of hand sanitizer the germs build an imunity.

Again thanks for the info.

Answer 12

That's news to me.  But then we only worm when we need to, so maybe that is why we have seen no signs of immunity.

I have used plain old zimectrin for I don't even know how long.

We usually gather fresh dropping every 3 months, take the samples in & have them checked for parasites.  If there is no evidence, we don't worm.  If there is evidence, we worm only the horses with the parasites.

Anyway, Thanks for the info.  It is something to keep an eye on regardless.

Answer 13

apparently you're suppose to change you suppose to change your wormer every year or two to stop immunity buliding up

Answer 14

Actually, according to the lastest study data both roundworms and small strongyles are developing an immunity against most all of the comercialy available de-worming products on the market, and at this point no new products are forth coming.

Their study showed that there was no drop in fecal egg count of roundworms after treatment with Ivermectin or Pyrantel Pamoate. On the other hand, only Ivermectin reduced the number of Small Strongyle eggs, Fenbendazole, Oxibendazole or Pyrantel Pamoate showed no effect.

You might find these links helpful:

http://www.horsetalk.co.nz/news/2008/04/...

http://www.thehorse.com/ViewArticle.aspx...

http://www.hearnvetservices.com/Worm.htm

Answer 15

Immunity to dewormers is not new - althout Ivermectin has been the most successful by far.

You should ALWAYS rotate at least 2-4 times a year to prevent immunity.

Be sure that the dewormer you are using actually kills the worm you are trying to remove.  Doing fecal counts 1-2 times a year will help you to know what worms you need to target.

Also, be sure your horse is actually getting his dewormer.  Is she doing it herself or depending on someone else to do it?  Horses are VERY good at not truly eating their dewormer.  Take the time to do it right and be sure your horse is getting the full dose.

Panacur Power Pacs will kill just about anything so that should give you a clean slate.  Then start a more aggressive rotation program and have the fecal counts done regularly.

Hope This Helps!

Answer 16

not familiar with the power pac.  have heard of the immunity problem.  You should always use alternate wormers in a consistent rotation.  this usually solves the problem.  I live in an area of heavy probable infestation because of the weather so I worm every 6 weeks.  I use an ivermectin product and especially in the transitional season, my alternate is a product called Tapecare which is one syringe equivalent to a double Strongid.  I learned this information at a horse care clinic given by an equine vet.   Seems to work great.

Answer 17

Yes i have seen this. A local vet told me a few years ago that the best way to worm is give generic pyrantel pamoate or generic ivermectin the first day, 2 days later give the other, in 2 more days give them Quest. I started using Zimectrin Gold  in place of the Quest every other cycle last year. I do this 3 times a year and have no worm problems and some of my friends went to this method and it solved their problems also. Good Luck

Answer 18

I have never thought Ivermectin did good with pinworms anyway.  The Panacur Power Pac will definitely kill them off.

The wormers are loosing there potency against some parasites - mostly do to people not rotating wormers, and people using them too often.

Just like antibiotics.